[RFC PATCH 0/5] KVM: speed up invalid guest state emulation

From: Paolo Bonzini
Date: Thu Mar 27 2014 - 07:31:04 EST


This series identifies some low-hanging fruit for speeding up emulation
of invalid guest state. I am a bit worried about patch 2, while
everything else should be relatively safe.

On the kvm-unit-tests microbenchmarks I get a 1.8-2.5x speedup (from
740-1100 cycles/instruction to 280-600).

This is not for 3.15, of course. Even patch 5 is not too useful without
the others; saving 40 clock cycles is a 10% speedup after the previous
patches, but only 4% before.

Please review carefully!

Paolo

Paolo Bonzini (5):
KVM: vmx: speed up emulation of invalid guest state
KVM: x86: avoid useless set of KVM_REQ_EVENT after emulation
KVM: x86: move around some checks
KVM: x86: protect checks on ctxt->d by a common "if (unlikely())"
KVM: x86: speed up emulated moves

arch/x86/include/asm/kvm_emulate.h | 2 +-
arch/x86/kvm/emulate.c | 182 ++++++++++++++++++++-----------------
arch/x86/kvm/vmx.c | 5 +-
arch/x86/kvm/x86.c | 28 ++++--
4 files changed, 120 insertions(+), 97 deletions(-)

--
1.8.3.1

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